Richard Smith's blog

Design is Compromise

Rare is the occasion when you can design a new widget without constraints, in fact I'd argue that it's not only rare but it's never. Engineering design is all about compromise. Take a Formula 1 car as an example, its success on the race track is overwhelmingly governed by the efficiency of its aerodynamics - yet even though it's so important the external aerodynamics for F1 cars is an exercise in compromise. Compromise to satisfy regulations, which are in place to actually slow cars down for safety's sake. Compromise to ensure that the wheels are supported correctly relative to the road. Compromise to ensure that the engine gets enough inlet air, cooling air, and a path to eject exhaust. Compromise in terms of the driver's safety structure. Compromise after compromise. No one element of a design can be optimized without considering the effect on the overall design.

F1 is a Compromise: 2007 Honda F1 CarF1 is a Compromise: 2007 Honda F1 Car

CFD Is Not Enough

Although most Computational Fluid Dynamics (CFD) software vendors would have you believe otherwise, a CFD tool alone does not a successful product make. Consider that Computer Aided Engineering (CAE) tools, such as CFD, are widely available yet some engineering organizations succeed and others fail. An excellent example is Formula 1, where all the teams use the latest state-of-the-art CFD tools, but some teams routinely win while others struggle. Clearly the governing factor is not the CFD tool they are using. The difference is the overall design and development process that encompasses CFD and, in no small part, the ingenuity of the engineers driving the process.

CFD Simulation of an Open Wheel RacecarCFD Simulation of an Open Wheel Racecar

All CFD Should Be Upfront CFD

There is a category of Computational Fluid Dynamics (CFD) called Upfront CFD. It typically refers to CFD software embedded in and launched from within CAD systems. Upfront, the term, also implies that it is something that happens before something else, maybe prior to detailed design in the design process - even during the concept design phase. I think the use of the term Upfront CFD is great marketing, but a poor differentiator of the actual CFD software.

Concept Design Phase CFDConcept Design Phase CFDParametric study of pipe diameter

Speed Up CFD with Symmetry and Cyclic Conditions

Symmetry (or planar symmetry) and cyclic (or rotational symmetry) boundary conditions for Computational Fluid Dynamics (CFD) can often save you 50% or more in simulation turnaround time. Alternatively you can use the freed up memory to run more accurate simulations with more mesh cells clustered in areas of interest. Clearly these simulations are worth considering if your model satisfies the symmetry or cyclic criteria.

Symmetric Flow Volume for the External Aerodynamic CFD Analysis of a CarSymmetric Flow Volume for the External Aerodynamic CFD Analysis of a CarSingle symmetry plane

Airships Rising

Airships are enjoying a renaissance of sorts. Military forces have proposed airships for surveillance and heavy lift duties. A small number of impressive prototypes have already taken to the air, but little follow-on development seems imminent. Could this renaissance be just a bli(m)p?

CFD Simulation of Flow Around an AirshipCFD Simulation of Flow Around an Airship

World Cup Stadium Aerodynamics with CFD

The 2014 FIFA World Cup is well underway and the final match to crown the world champions will be played in the Maracanã Stadium. The stadium was originally built to host the 1950 World Cup final, but with the stadium being the focal point for the current 2014 World Cup and the upcoming 2016 Olympics it was deemed that it needed a revamp. The most striking difference between the old and newly renovated stadium is the roof that now protects 95% of the seating from rain and provides better shade. The original roof only offered minimal rain protection and shade to a few rows of seats. However, it seems little air-time has been devoted to analyzing the wind characteristics of the playing area inside the stadium due to the different roof extents, especially when you consider how much attention the aerodynamics of the match ball have garnered. Rest easy though, Computational Fluid Dynamics (CFD) is here to help.

Caedium CFD Simulation of a StadiumCaedium CFD Simulation of a StadiumStreamlines

World Cup Balls

Every 4 years the FIFA World Cup rolls around and the question on everyone's lips is...how will the official match balls behave? Oh, and to a lesser degree, which nation will win?  Ball aerodynamics are complex, but relatively well understood. Given the typical speed and spin of balls in the beautiful game, small changes to their surface texture (the focus of much recent effort in ball design) can have dramatic repercussions on their trajectories and hang times. Balls are deemed so important that each has its own Wikipedia page and each has tournament-flavored names thanks to Adidas, the long time ball designer.

CFD Simulation of Flow Around a Rotating BallCFD Simulation of Flow Around a Rotating Ball

Tower Bridge Meets CFD

Complete, watertight, complex geometry is a rare but welcome find in Computational Fluid Dynamics (CFD). However, thanks to the steering committee of the upcoming 23rd International Meshing Roundtable, such a geometry, in various formats, is freely available for their meshing contest. The star of the contest is London's Tower Bridge, I presume in honor of the conference's host city. So to the bat cave to see what Caedium Professional can do with this model.

Tower Bridge Caedium CFD SimulationTower Bridge Caedium CFD SimulationVelocity contours

How to Make a Splash in CFD

It is a common occurrence: a rain drop falls into a puddle; a leaky faucet drips into a sink of water. This seemingly simple event has some complex physics in play that advanced multi-phase, free-surface (volume of fluid - VOF) Computational Fluid Dynamics (CFD) can simulate. Not only can CFD simulate water impact in a pool, it can also produce a beautiful 3D visualization of the process as an animation. Follow along to see how you can use Caedium Professional to simulate a water droplet falling into a pool of water.

VOF Free Surface Caedium CFD SimulationVOF Free Surface Caedium CFD SimulationDroplet crater

Caedium CFD Sneak Peek: Passive Species Transport

The next release of the Caedium CFD software system will be able to simulate the convection and diffusion of a passive species, also known as a passive scalar. A passive species can represent and track additions such as smoke in airflow and dye in water. It can also provide insights on the dispersion of pollutants carried by a fluid.

Caedium Passive Species CFD SimulationPollutant plume released in air from a chimney

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